Question

Ecological efficiency is:-

1. ${\dfrac{Food\;energy\;assimilated}{Food\;energy\;ingested}}\times 100$

2.${\dfrac{Gross\;Primary\;Productivity}{Incident\;Total\;Solar\;Radiation}}\times 100$

3.${\dfrac{Volume\;of\;Carbon\;dioxide\;evolved}{Volume\;of\;Oxygen\;Consumed}}$

4.${\dfrac{Energy\;in\;biomass\;production\;at\;a\;trophic\;level}{Energy\;in\;biomass\;production\;at\;a\;previous\;trophic\;level}}\times 100$

5.${\dfrac{Net\;primary\;productivity}{Gross\;primary\;productivity}}\times 100$

Answer 1

Hint: Ecological efficiency is determined by a combination of efficiencies relating to organismic resource acquisition and assimilation into an ecosystem. The biodiversity of a particular area is directly proportional to the ecological efficiency. There are two types of ecological efficiency, one is Net Production Efficiency (NPE) and the other is A/I (the way in which animals convert the food they ingest into energy).

Complete answer:
1.The system of energy flow in living organisms is basically through the food chain and is called the calorific flow. The process of Ingestion is followed by the process of Assimilation and this chain continues from autotrophs to decomposers. This system cannot be presented in the given formula. Hence, the option is incorrect.

2.An estimate of 1-5% of incident solar radiation is captured by autotrophic organisms during the synthesis of organic matter also known as gross primary productivity. Around 20% of this is consumed during the process of respiration and hence the Net Primary Productivity would be 0.8-4% of incident radiation. So, the equation can’t depict the right logic here.

3.The volume of CO2 evolved would be the percentage of the gas emitted by different sources within the atmosphere. And the volume of CO2 consumed would be intake of CO2 by autotrophic organisms for photosynthesis. This is a part of the carbon cycle and is not directly related to ecological efficiency.

4.The Gross primary productivity is the amount of chemical energy that primary producers create in a given length of time. A fraction of this energy is used by primary producers for their respiration and the remaining fixed energy is referred to as Net Primary Productivity. Therefore, the net primary productivity is the difference between gross primary productivity and energy consumed by autotrophs for cellular respiration.

5.Ecological efficiency is described as the efficiency with which energy is transformed from one trophic level to another. It is determined by a series of efficiencies relating to organismic resource acquisition and assimilation in an ecosystem.

Hence, the correct answer is option (4)

Note: While understanding the concept of Ecological efficiency, one needs to understand its types in detail. As we know, ecological efficiency is of two types, one is Net Production Efficiency and the other is A/I. Net production efficiency (NPE) measures how efficiently each trophic level uses and incorporates the energy from its food into biomass to fuel the next trophic level.